What is Say's law? Discuss in brief.

Say's law, named after French economist Jean-Baptiste Say, is a principle in classical economics that states that supply creates its own demand. In other words, production of goods and services creates enough income in the economy to purchase all the output produced. It suggests that producing goods will automatically generate enough income for people to buy those goods.

Say's law is a fundamental concept in classical economics, as it supports the belief in the self-regulating nature of the market. According to Say's law, there cannot be a general overproduction or underproduction in the economy since production automatically generates the income necessary for consumption. This is the main reason why classical economists are generally against government intervention, as they believe that the economy can naturally reach a state of equilibrium.

The main implication of Say's law is that recessions and depressions are caused by a mismatch of supply and demand in specific sectors of the economy, rather than by a general lack of demand. According to classical economists, if there is an excess supply in one sector, it forces resources to shift to other sectors where demand is higher. This process is believed to eventually restore equilibrium in the market.

Say's law has been criticized by several economic thinkers, most notably by John Maynard Keynes. Keynes argued that demand drives supply, rather than the other way around, and that insufficient demand could lead to a general glut or economic recession. This contradicts Say's law, as it implies that the economy does not automatically adjust to find the optimal equilibrium. Keynesian economists believe that government intervention, such as fiscal and monetary policy, can be used to increase demand during periods of economic downturn and restore the economy to equilibrium more quickly. In conclusion, Say's law is an important principle in classical economics that states that supply generates its own demand and the economy will naturally reach a state of equilibrium. However, this concept has been challenged by other economic schools of thought, particularly Keynesian economics, which argue for the importance of government intervention in managing demand.